New records of Phytophthora on trees in Britain

Phytophthora megasperma var. megasperma and unidentified isolates of Pbytophthora rescmbling P. cambivora were obtained from dead and dying roots of Horsc chestnut trccs with sparse foliage, small chlorotic leaves and branch dieback. P. citricola was isolatcd from soil around dead roots of similarly affected trccs and from around dcad feeder roots of a tree suffering from the common but unexplained Leaf scorch (marginal leaf necrosis) of Horse chestnut. Both P. cactorum and P. citricola were isolated from oozing acrial stem lesions on Horse chestnut trees. Inoculations with these species reproduced the damage.